Background checks and identity verification
Before booking, check an installer's registration number directly on the FENSA or CERTASS website, not just take their word for it — window and door sales has historically had more than its share of doorstep sales pressure, so independent verification is worth the two minutes it takes.
What a good window quote should include
A proper quote should state frame material and colour, glazing spec, whether old windows/frames are removed and disposed of, the FENSA/CERTASS certificate, and the guarantee length on both frames and glazing units, which can differ.
Common window and door jobs
Window specialists handle full window replacement, double glazing unit repairs (a fogged unit usually means a failed seal, not the whole frame), door replacement, conservatories, and draught-proofing. Composite and bifold doors are increasingly common alongside standard uPVC window replacement.
Window energy ratings, explained
Windows are rated A++ to E based on their whole-window performance (frame and glass together), similar in concept to appliance energy labels. A higher rating generally means better heat retention, but the U-value figure is the more precise technical spec worth asking for if comparing quotes closely.
Understanding the labour vs materials split
Frame and glazing unit costs are often the largest share of a window quote, but fitting labour, old window removal/disposal and making good around the reveal add up too. If a quote looks cheap, check it specifies the same glazing spec as competing quotes, not a lower-grade unit.
Toughened, laminated and obscure glass
Toughened (safety) glass is required by Building Regulations in doors and low-level windows. Laminated glass adds security and noise reduction. Obscure (patterned) glass is used where privacy matters, like bathroom windows, without losing light — worth specifying which you need per opening rather than assuming standard clear glass throughout.
Do you need planning permission for new windows?
Like-for-like replacement usually doesn't need planning permission. Adding a new window opening, especially on a side elevation close to a boundary, or in a conservation area or listed property, often does. Check before ordering if you're changing an opening rather than replacing what's already there.
Window and door guarantees, what to check
Frame guarantees commonly run 10 years, glazing unit guarantees are often shorter — ask specifically, since a failed seal (misting between panes) is a glazing unit issue, not a frame issue, and needs to be covered by the right guarantee. Installation workmanship guarantees are usually separate again.